Method of making lightweight polymer ammunition

ABSTRACT

One embodiment of the present invention provides a method of making a polymeric ammunition cartridge having a substantially cylindrical metal primer insert, a substantially cylindrical polymeric middle body coupled to a substantially cylindrical open-ended polymeric bullet-end component.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. patent applicationSer. No. 14/011,202 filed on Aug. 27, 2013 which is a DivisionalApplication of U.S. patent application Ser. No. 13/292,843 filed on Nov.9, 2011 (now U.S. Pat. No. 8,561,543) which claims the benefit of U.S.Provisional Patent Application Ser. No. 61/456,664, filed Nov. 10, 2010,the contents of each are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of ammunition,specifically to compositions of matter and methods of making and usingpolymeric ammunition cartridge casings.

STATEMENT OF FEDERALLY FUNDED RESEARCH

None.

INCORPORATION-BY-REFERENCE OF MATERIALS FILED ON COMPACT DISC

None.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with lightweight polymer cartridge casing ammunition.Conventional ammunition cartridge casings for rifles and machine guns,as well as larger caliber weapons, are made from brass, which is heavy,expensive, and potentially hazardous. There exists a need for anaffordable lighter weight replacement for brass ammunition cartridgecases that can increase mission performance and operationalcapabilities. Lightweight polymer cartridge casing ammunition must meetthe reliability and performance standards of existing fielded ammunitionand be interchangeable with brass cartridge casing ammunition inexisting weaponry. Reliable cartridge casings manufacture requiresuniformity (e.g., bullet seating, bullet-to-casing fit, casing strength,etc.) from one cartridge to the next in order to obtain consistentpressures within the casing during firing prior to bullet and casingseparation to create uniformed ballistic performance. Plastic cartridgecasings have been known for many years but have failed to providesatisfactory ammunition that could be produced in commercial quantitieswith sufficient safety, ballistic, handling characteristics, and survivephysical and natural conditions to which it will be exposed during theammunition's intended life cycle; however, these characteristics havenot been achieved.

For example, U.S. patent application Ser. No. 11/160,682 discloses abase for a cartridge casing body for an ammunition article, the basehaving an ignition device; an attachment device at one end thereof, theattachment device being adapted to the base to a cartridge casing body;wherein the base is made from plastic, ceramic, or a composite material.

U.S. patent application Ser. No. 7,610,858 discloses an ammunitioncartridge assembled from a substantially cylindrical polymeric cartridgecasing body defining a casing headspace with an open projectile-end andan end opposing the projectile-end, wherein the casing body has asubstantially cylindrical injection molded polymeric bullet-endcomponent with opposing first and second ends, the first end of which isthe projectile-end of the casing body and the second end has a male orfemale coupling element; and a cylindrical polymeric middle bodycomponent with opposing first and second ends, wherein the first end hasa coupling element that is a mate for the projectile-end couplingelement and joins the first end of the middle body component to thesecond end of the bullet-end component, and the second end is the end ofthe casing body opposite the projectile end and has a male or femalecoupling element; and a cylindrical cartridge casing head-end componentwith an essentially closed base end with a primer hole opposite an openend with a coupling element that is a mate for the coupling element onthe second end of the middle body and joins the second end of the middlebody component to the open end of the head-end component; wherein themiddle body component is formed from a material more ductile than thematerial head-end component is formed from but equal or less ductilethan the material the bullet-end component is formed from. Methods forassembling ammunition cartridges and ammunition cartridges having theheadspace length larger than the corresponding headspace length of thechamber of the intended weapon measured at the same basic diameter forthe cartridge casing without being so large as to jam the weapon orotherwise interfere with its action are also disclosed.

Shortcomings of the known methods of producing plastic or substantiallyplastic ammunition include the possibility of the projectile beingpushed into the cartridge casing, the bullet pull being too light suchthat the bullet can fall out, the bullet pull being too insufficient tocreate sufficient chamber pressure, the bullet pull not being uniformfrom round to round, and portions of the cartridge casing breaking offupon firing causing the weapon to jam or damage or danger whensubsequent rounds are fired or when the casing portions themselvesbecome projectiles. To overcome the above shortcomings, improvements incartridge case design and performance polymer materials are needed.

BRIEF SUMMARY OF THE INVENTION

One embodiment of the present invention provides a method of making apolymeric ammunition cartridge having a substantially cylindrical metalprimer insert comprising the steps of: providing a substantiallycylindrical insert comprising a top surface opposite a bottom surfaceand a substantially cylindrical coupling element that extends from thebottom surface to form a circumferential surface, a primer recess in thetop surface that extends toward the bottom surface, a primer flash holeaperture positioned in the primer recess to extend through the bottomsurface, and a flange that extends circumferentially about an outer edgeof the top surface; forming a substantially cylindrical polymeric middlebody comprising the steps of overmolding a polymer composition over thesubstantially cylindrical insert by molding the polymer composition overthe substantially cylindrical coupling element, over the circumferentialsurface and into the primer flash hole aperture to form a primer flashhole, forming a substantially cylindrical polymeric middle bodyextending from the substantially cylindrical insert, and forming asubstantially cylindrical polymeric coupling end at the end of thesubstantially cylindrical polymeric middle body; forming a substantiallycylindrical open-ended polymeric bullet-end component comprising thesteps of forming a polymeric bullet-end coupling component opposite abullet-end aperture from a second polymer composition, wherein thepolymeric bullet-end coupling component mates to the substantiallycylindrical polymeric coupling end; and adhering the polymericbullet-end coupling component mates to the substantially cylindricalpolymeric coupling end to form a propellant chamber having a bullet-endaperture opposite a primer flash hole.

Another embodiment of the present invention provides a method of makinga polymeric ammunition having a substantially cylindrical metal primerinsert comprising the steps of: providing a substantially cylindricalinsert comprising a top surface opposite a bottom surface and asubstantially cylindrical coupling element that extends from the bottomsurface to form a circumferential surface, a primer recess in the topsurface that extends toward the bottom surface, a primer flash holeaperture positioned in the primer recess to extend through the bottomsurface, and a flange that extends circumferentially about an outer edgeof the top surface; forming a substantially cylindrical polymeric middlebody comprising the steps of overmolding a polymer composition over thesubstantially cylindrical insert by molding the polymer composition overthe substantially cylindrical coupling element, over the circumferentialsurface and into the primer flash hole aperture to form a primer flashhole, forming a substantially cylindrical polymeric middle bodyextending from the substantially cylindrical insert, and forming asubstantially cylindrical polymeric coupling end at the end of thesubstantially cylindrical polymeric middle body; forming a substantiallycylindrical open-ended polymeric bullet-end component comprising thesteps of forming a polymeric bullet-end coupling component opposite abullet-end aperture from a second polymer composition, wherein thepolymeric bullet-end coupling component mates to the substantiallycylindrical polymeric coupling end; adhering the polymeric bullet-endcoupling component mates to the substantially cylindrical polymericcoupling end to form a propellant chamber having a bullet-end apertureopposite a primer flash hole; inserting a primer inserted into theprimer flash hole aperture; at least partially filling the propellantchamber with a propellant; and frictionally fitting a bullet in thebullet-end aperture, wherein the primer, the propellant and the bulletform a sealed propellant chamber.

The substantially cylindrical open-ended polymeric bullet-end componentmay have a shoulder positioned between the substantially cylindricalpolymeric bullet-end and the bullet-end aperture. The substantiallycylindrical open-ended polymeric bullet-end component may have a neckpositioned between the bullet-end aperture and the shoulder. Thesubstantially cylindrical open-ended polymeric bullet-end component,substantially cylindrical polymeric middle body or both may be formedfrom a ductile polymer. The substantially cylindrical open-endedpolymeric bullet-end component may be formed from a less ductile polymerthan the substantially cylindrical polymeric middle body. Thesubstantially cylindrical open-ended polymeric bullet-end component,substantially cylindrical polymeric middle body or both may include anylon polymer. The substantially cylindrical open-ended polymericbullet-end component, substantially cylindrical polymeric middle body orboth may be formed from a fiber-reinforced polymeric composite. Thefiber-reinforced polymeric composite may include between about 10 andabout 70 wt % glass fiber fillers, mineral fillers, or mixtures thereof.The substantially cylindrical open-ended polymeric bullet-end componentmay be welded or bonded to the substantially cylindrical polymericmiddle body. The bullet-end aperture may be welded or bonded to thebullet. The bullet-end aperture may be crimped to the bullet. The bulletmay be adhesively fitted to the bullet-end aperture. The bullet-endaperture or the neck may have one or more cannelures that interlockswith the bullet. The forward opening end may have one, two, three, ormore annular rings that mate with one, two, three, or more correspondingannular grooves positioned on the bullet. The substantially cylindricalpolymeric middle body may be a polymers selected from the groupconsisting of polyurethane prepolymer, cellulose, fluoro-polymer,ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon,polyether imide, polyester elastomer, polyester sulfone, polyphenylamide, polypropylene, polyvinylidene fluoride or thermoset polyureaelastomer, acrylics, homopolymers, acetates, copolymers,acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers,polyamides, polyamide-imides, polyacrylates, polyatherketones,polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene,terephthalates, polyether imides, polyether sulfones, thermoplasticpolyimides, thermoplastic polyurethanes, polyphenylene sulfides,polyethylene, polypropylene, polysulfones, polyvinylchlorides, styreneacrylonitriles, polystyrenes, polyphenylene, ether blends, styrenemaleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies,phenolics, unsaturated polyesters, bismaleimides, polyurethanes,silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymersof polyphenylsulfones with polyethersulfones or polysulfones, copolymersof poly-phenylsulfones with siloxanes, blends of polyphenylsulfones withpolysiloxanes, poly(etherimide-siloxane) copolymers, blends ofpolyetherimides and polysiloxanes, and blends of polyetherimides andpoly(etherimide-siloxane) copolymers. The substantially cylindricalopen-ended polymeric bullet-end component may be a polymers selectedfrom the group consisting of polyurethane prepolymer, cellulose,fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinylacetate, nylon, polyether imide, polyester elastomer, polyester sulfone,polyphenyl amide, polypropylene, polyvinylidene fluoride or thermosetpolyurea elastomer, acrylics, homopolymers, acetates, copolymers,acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers,polyamides, polyamide-imides, polyacrylates, polyatherketones,polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene,terephthalates, polyether imides, polyether sulfones, thermoplasticpolyimides, thermoplastic polyurethanes, polyphenylene sulfides,polyethylene, polypropylene, polysulfones, polyvinylchlorides, styreneacrylonitriles, polystyrenes, polyphenylene, ether blends, styrenemaleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies,phenolics, unsaturated polyesters, bismaleimides, polyurethanes,silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymersof polyphenylsulfones with polyethersulfones or polysulfones, copolymersof poly-phenylsulfones with siloxanes, blends of polyphenylsulfones withpolysiloxanes, poly(etherimide-siloxane) copolymers, blends ofpolyetherimides and polysiloxanes, and blends of polyetherimides andpoly(etherimide-siloxane) copolymers. The substantially cylindricalopen-ended polymeric bullet-end component may have a neck with aplurality of internal structures for supporting a bullet. Thesubstantially cylindrical coupling element may be a male couplingelement with a straight skirt interlock surface that tapers to a smallerdiameter at the forward portion on the skirt tip to mate with a femalecoupling element of the substantially cylindrical polymeric couplingend. The polymeric ammunition may include a diffuser positioned in theprimer recess in contact with the primer and comprising a diffuser flashhole aligned with the primer flash hole.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent invention, reference is now made to the detailed description ofthe invention along with the accompanying figures and in which:

FIG. 1 depicts a side, cross-sectional view of a polymeric cartridgecase according to one embodiment of the present invention;

FIG. 2 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case according to one embodiment of the presentinvention;

FIG. 3 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case lacking the aperture coating;

FIGS. 4 a and 4 b depict images of a catastrophic failure of thepolymeric cartridge case of FIG. 3;

FIG. 5 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case displaying ribs according to one embodiment ofthe present invention;

FIG. 6 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case displaying ribs according to one embodiment ofthe present invention;

FIG. 7 depicts a side, cross-sectional view of a polymeric cartridgecase having a diffuser according to one embodiment of the presentinvention;

FIG. 8 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case having a diffuser according to one embodimentof the present invention;

FIGS. 9 a-9 h depict diffuser according to a different embodiment of thepresent invention;

FIG. 10 depicts an exploded view of the polymeric cartridge casing; and

FIG. 11 depicts a view of the substantially cylindrical open-endedpolymeric bullet-end having a shoulder forming chamber neck and abullet.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not delimit the invention, except as outlined in the claims.

Reliable cartridge manufacture requires uniformity from one cartridge tothe next in order to obtain consistent ballistic performance. Amongother considerations, proper bullet seating and bullet-to-casing fit isrequired. In this manner, a desired pressure develops within the casingduring firing prior to bullet and casing separation. Historically,bullets employ a cannelure, which is a slight annular depression formedin a surface of the bullet at a location determined to be the optimalseating depth for the bullet. In this manner, a visual inspection of acartridge could determine whether or not the bullet is seated at theproper depth. Once the bullet is inserted into the casing to the properdepth, one of two standard procedures is incorporated to lock the bulletin its proper location. One method is the crimping of the entire end ofthe casing into the cannelure. A second method does not crimp the casingend; rather the bullet is pressure fitted into the casing.

The polymeric ammunition cartridges of the present invention are of acaliber typically carried by soldiers in combat for use in their combatweapons. The present invention is not limited to the described caliberand is believed to be applicable to other calibers as well. Thisincludes various small and medium caliber munitions, including 5.56 mm,7.62 mm and 0.50 caliber ammunition cartridges, as well as medium/smallcaliber ammunition such as 380 caliber, 38 caliber, 9 mm, 10 mm, 20 mm,25 mm, 30 mm, 40 mm, 45 caliber and the like. The cartridges, therefore,are of a caliber between about 0.05 and about 5 inches. Thus, thepresent invention is also applicable to the sporting goods industry foruse by hunters and target shooters.

FIG. 1 depicts a side, cross-sectional view of a polymeric cartridgecase according to one embodiment of the present invention. A cartridge10 suitable for use with high velocity rifles is shown manufactured witha polymer casing 12 showing a powder chamber 14 with projectile (notshown) inserted into the forward end opening 16. Polymer casing 12 has asubstantially cylindrical open-ended polymeric bullet-end 18 extendingfrom forward end opening 16 rearward to opposite end 20. The bullet-endcomponent 18 may be formed with coupling end 22 formed on end 20.Coupling end 22 is shown as a female element, but may also be configuredas a male element in alternate embodiments of the invention. The forwardend of bullet-end component 18 has a shoulder 24 forming chamber neck26. The bullet-end component typically has a wall thickness betweenabout 0.003 and about 0.200 inches and more preferably between about0.005 and more preferably between about 0.150 inches about 0.010 andabout 0.050 inches.

The middle body component 28 is connected to a substantially cylindricalcoupling element 30 of the substantially cylindrical insert 32. Couplingelement 30, as shown may be configured as a male element, however, allcombinations of male and female configurations is acceptable forcoupling elements 30 and coupling end 22 in alternate embodiments of theinvention. Coupling end 22 of bullet-end component 18 fits about andengages coupling element 30 of a substantially cylindrical insert 32.The substantially cylindrical insert 32 includes a substantiallycylindrical coupling element 30 extending from a bottom surface 34 thatis opposite a top surface 36. Located in the top surface 36 is a primerrecess 38 that extends toward the bottom surface 34. A primer flash hole40 is located in the primer flash hole aperture 42 and extends throughthe bottom surface 34 into the powder chamber 14. The coupling end 22extends the polymer through the primer flash hole 40 to form an aperturecoating 42 while retaining a passage from the top surface 36 through thebottom surface 34 and into the powder chamber 14 to provide support andprotection about the primer flash hole 40. When contacted the couplingend 22 interlocks with the substantially cylindrical coupling element30, through the coupling element 30 that extends with a taper to asmaller diameter at the tip 44 to form a physical interlock betweensubstantially cylindrical insert 32 and middle body component 28.Polymer casing 12 also has a substantially cylindrical open-ended middlebody component 28. The middle body component extends from a forward endopening 16 to coupling element 22. The middle body component typicallyhas a wall thickness between about 0.003 and about 0.200 inches and morepreferably between about 0.005 and more preferably between about 0.150inches about 0.010 and about 0.050 inches.

The bullet-end 16, middle body 18 and bottom surface 34 define theinterior of powder chamber 14 in which the powder charge (not shown) iscontained. The interior volume of powder chamber 14 may be varied toprovide the volume necessary for complete filling of the chamber 14 bythe propellant chosen so that a simplified volumetric measure ofpropellant can be utilized when loading the cartridge. Either aparticulate or consolidated propellant can be used.

The substantially cylindrical insert 32 also has a flange 46 cut thereinand a primer recess 38 formed therein for ease of insertion of theprimer (not shown). The primer recess 38 is sized so as to receive theprimer (not shown) in an interference fit during assembly. A primerflash hole 40 communicates through the bottom surface 34 ofsubstantially cylindrical insert 32 into the powder chamber 14 so thatupon detonation of primer (not shown) the powder in powder chamber 14will be ignited.

Projectile (not shown) is held in place within chamber case neck 26 atforward opening 16 by an interference fit. Mechanical crimping of theforward opening 16 can also be applied to increase the bullet pullforce. The bullet (not shown) may be inserted into place following thecompletion of the filling of powder chamber 14. Projectile (not shown)can also be injection molded directly onto the forward opening 16 priorto welding or bonding together using solvent, adhesive, spin-welding,vibration-welding, ultrasonic-welding or laser-welding techniques. Thewelding or bonding increases the joint strength so the casing can beextracted from the hot gun casing after firing at the cook-offtemperature.

The bullet-end and bullet components can then be welded or bondedtogether using solvent, adhesive, spin-welding, vibration-welding,ultrasonic-welding or laser-welding techniques. The welding or bondingincreases the joint strength so the casing can be extracted from the hotgun casing after firing at the cook-off temperature. An optional firstand second annular grooves (cannelures) may be provided in thebullet-end in the interlock surface of the male coupling element toprovide a snap-fit between the two components. The cannelures formed ina surface of the bullet at a location determined to be the optimalseating depth for the bullet. Once the bullet is inserted into thecasing to the proper depth to lock the bullet in its proper location.One method is the crimping of the entire end of the casing into thecannelures.

The bullet-end and middle body components can then be welded or bondedtogether using solvent, adhesive, spin-welding, vibration-welding,ultrasonic-welding or laser-welding techniques. The welding or bondingincreases the joint strength so the casing can be extracted from the hotgun casing after firing at the cook-off temperature.

FIG. 2 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case according to one embodiment of the presentinvention. A portion of a cartridge suitable for use with high velocityrifles is shown manufactured with a polymer casing 12 showing a powderchamber 14. Polymer casing 12 has a substantially cylindrical oppositeend 20. The bullet-end component 18 may be formed with coupling end 22formed on end 20. Coupling end 22 is shown as a female element, but mayalso be configured as a male element in alternate embodiments of theinvention. The middle body component (not shown) is connected to asubstantially cylindrical coupling element 30 of the substantiallycylindrical insert 32. Coupling element 30, as shown may be configuredas a male element, however, all combinations of male and femaleconfigurations is acceptable for coupling elements 30 and coupling end22 in alternate embodiments of the invention. Coupling end 22 fits aboutand engages coupling element 30 of a substantially cylindrical insert32. The substantially cylindrical insert 32 includes a substantiallycylindrical coupling element 30 extending from a bottom surface 34 thatis opposite a top surface 36. Located in the top surface 36 is a primerrecess 38 that extends toward the bottom surface 34. A primer flash hole40 is located in the primer recess 38 and extends through the bottomsurface 34 into the powder chamber 14. The coupling end 22 extends thepolymer through the primer flash hole 40 to form an aperture coating 42while retaining a passage from the top surface 36 through the bottomsurface 34 and into the powder chamber 14 to provide support andprotection about the primer flash hole 40. When contacted the couplingend 22 interlocks with the substantially cylindrical coupling element30, through the coupling element 30 that extends with a taper to asmaller diameter at the tip 44 to form a physical interlock betweensubstantially cylindrical insert 32 and middle body component 28.Polymer casing 12 also has a substantially cylindrical open-ended middlebody component 28.

FIG. 3 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case lacking the polymer extending in the flash holeaperture.

A portion of a cartridge suitable for use with high velocity rifles isshown manufactured with a polymer casing 12 showing a powder chamber 14.Polymer casing 12 has a substantially cylindrical opposite end 20. Thebullet-end component 18 may be formed with coupling end 22 formed on end20. Coupling end 22 is shown as a female element, but may also beconfigured as a male element in alternate embodiments of the invention.The middle body component (not shown) is connected to a substantiallycylindrical coupling element 30 of the substantially cylindrical insert32. Coupling element 30, as shown may be configured as a male element,however, all combinations of male and female configurations isacceptable for coupling elements 30 and coupling end 22 in alternateembodiments of the invention. Coupling end 22 fits about and engagescoupling element 30 of a substantially cylindrical insert 32. Thesubstantially cylindrical insert 32 includes a substantially cylindricalcoupling element 30 extending from a bottom surface 34 that is oppositea top surface 36. Located in the top surface 36 is a primer recess 38that extends toward the bottom surface 34. A primer flash hole 40 islocated in the primer recess 38 and extends through the bottom surface34 into the powder chamber 14. The coupling end 22 extends the polymerto the primer flash hole 40 while retaining a passage from the topsurface 36 through the bottom surface 34 and into the powder chamber 14to provide support and protection about the primer flash hole 40. Whencontacted the coupling end 22 interlocks with the substantiallycylindrical coupling element 30, through the coupling element 30 thatextends with a taper to a smaller diameter at the tip 44 to form aphysical interlock between substantially cylindrical insert 32 andmiddle body component 28. Polymer casing 12 also has a substantiallycylindrical open-ended middle body component 28.

FIGS. 4 a and 4 b depict images of a catastrophic failure of thepolymeric cartridge case of FIG. 3. Other polymeric cartridge case wastested and resulted in catastrophic failure with the rounds blowing themagazine out of the weapon and fragmenting the metal insert and lodgingthe polymer case in the chamber. The examination of the catastrophicfailure revealed the tearing of the polymer at the top of the insert. Asa result, in some embodiments the height of the insert was reduced by0.020″ to reduce the tearing and frequency of catastrophic failures.Further examination, revealed that the polymer at the flash hole of thebase was separating from the insert. One embodiment locks the polymerinto the flash hole by extending the polymer into the flash hole. Inaddition, the raised area was removed, the diameter of the flash holewas opened, and the primer side was counter bored. Other embodiments mayincorporate all, one, or a combination of 2 or more of these elements tostop the gas from separating the polymer from the insert that wascreating combustion between the insert and the polymer.

FIG. 5 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case displaying ribs according to one embodiment ofthe present invention. A portion of a cartridge suitable for use withhigh velocity rifles is shown manufactured with a polymer casing 12showing a powder chamber 14. Polymer casing 12 has a substantiallycylindrical opposite end 20. The bullet-end component 18 may be formedwith coupling end 22 formed on end 20. Coupling end 22 is shown as afemale element, but may also be configured as a male element inalternate embodiments of the invention. The middle body component (notshown) is connected to a substantially cylindrical coupling element 30of the substantially cylindrical insert 32. Coupling element 30, asshown may be configured as a male element, however, all combinations ofmale and female configurations is acceptable for coupling elements 30and coupling end 22 in alternate embodiments of the invention. Couplingend 22 fits about and engages coupling element 30 of a substantiallycylindrical insert 32. The substantially cylindrical insert 32 includesa substantially cylindrical coupling element 30, extending from a bottomsurface 34 that is opposite a top surface 36. Located in the top surface36 is a primer recess 38 that extends toward the bottom surface 34. Aprimer flash hole 40 is located in the primer flash hole 40 and extendsthrough the bottom surface 34 into the powder chamber 14. The couplingend 22 extends the polymer through the primer flash hole 40 to form anaperture coating 42 while retaining a passage from the top surface 36through the bottom surface 34 and into the powder chamber 14 to providesupport and protection about the primer flash hole 40. When contactedthe coupling end 22 interlocks with the substantially cylindricalcoupling element 30, through the coupling element 30 that extends with ataper to a smaller diameter at the tip 44 to form a physical interlockbetween substantially cylindrical insert 32 and middle body component28. Polymer casing 12 also has a substantially cylindrical open-endedmiddle body component 28. The substantially cylindrical opposite end 20or anywhere within the powder chamber 14 may include one or more ribs 48on the surface. The number of ribs 48 will depend on the specificapplication and desire of the manufacture but may include 1, 2, 3, 4, 56, 7, 8, 9, 10, or more ribs. In the counter bore, the polymer washaving difficulty filling this area due to the fact that the polymerused has fillers in it, and needed to be reblended during molding. Oneembodiment includes six ribs 48 to create turbulence in the flow of thepolymer, thus allowing the material to fill the counter bore.

FIG. 6 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case displaying ribs according to one embodiment ofthe present invention. One embodiment that reduces bellowing of theinsert includes a shortened insert and angled coupling element 30 insideof the insert. In addition, the raised portion of the polymer at theflash hole was removed, the internal polymer wall was lowered and angledto match the insert and the internal ribs were lengthened.

A portion of a cartridge suitable for use with high velocity rifles isshown manufactured with a polymer casing 12 showing a powder chamber 14.Polymer casing 12 has a substantially cylindrical opposite end 20. Thebullet-end component 18 may be formed with coupling end 22 formed on end20. Coupling end 22 is shown as a female element, but may also beconfigured as a male element in alternate embodiments of the invention.The middle body component (not shown) is connected to a substantiallycylindrical coupling element 30 of the substantially cylindrical insert32. Coupling element 30, as shown may be configured as a male element,however, all combinations of male and female configurations isacceptable for coupling elements 30 and coupling end 22 in alternateembodiments of the invention. Coupling end 22 fits about and engagescoupling element 30 of a substantially cylindrical insert 32. Thesubstantially cylindrical insert 32 includes a substantially cylindricalcoupling element 30 extending from a bottom surface 34 that is oppositea top surface 36. Located in the top surface 36 is a primer recess 38that extends toward the bottom surface 34. A primer flash hole 40 islocated in the primer flash hole 40 and extends through the bottomsurface 34 into the powder chamber 14. The coupling end 22 extends thepolymer through the primer flash hole 40 to form an aperture coating 42while retaining a passage from the top surface 36 through the bottomsurface 34 and into the powder chamber 14 to provide support andprotection about the primer flash hole 40. When contacted the couplingend 22 interlocks with the substantially cylindrical coupling element30, through the coupling element 30 that extends with a taper to asmaller diameter at the tip 44 to form a physical interlock betweensubstantially cylindrical insert 32 and middle body component 28.Polymer casing 12 also has a substantially cylindrical open-ended middlebody component 28. The substantially cylindrical opposite end 20 oranywhere within the powder chamber 14 may include one or more ribs 48 onthe surface. The number of ribs 48 will depend on the specificapplication and desire of the manufacture but may include 1, 2, 3, 4, 56, 7, 8, 9, 10, or more ribs. In the counter bore, the polymer washaving difficulty filling this area due to the fact that the polymerused has fillers in it, and needed to be reblended during molding. Oneembodiment includes six ribs 48 to create turbulence in the flow of thepolymer, thus allowing the material to fill the counter bore. Anotherembodiment of the instant invention is a shortened insert and angledcoupling element 30 inside of the insert. In addition, raised portionsof the polymer at the flash hole, lowered and angled the internalpolymer wall to match the insert and lengthened the internal ribs.

FIG. 7 depicts a side, cross-sectional view of a polymeric cartridgecase having a diffuser according to one embodiment of the presentinvention. The diffuser 50 is a device that is used to divert theaffects of the primer off of the polymer and directing it to the flashhole. The affects being the impact from igniting the primer as far aspressure and heat. A cartridge 10 suitable for use with high velocityrifles is shown manufactured with a polymer casing 12 showing a powderchamber 14 with projectile (not shown) inserted into the forward endopening 16. Polymer casing 12 has a substantially cylindrical open-endedpolymeric bullet-end 18 extending from forward end opening 16 rearwardto the opposite end 20. The bullet-end component 18 may be formed withcoupling end 22 formed on end 20. Coupling end 22 is shown as a femaleelement, but may also be configured as a male element in alternateembodiments of the invention. The forward end of bullet-end component 18has a shoulder 24 forming chamber neck 26.

The middle body component 28 is connected to a substantially cylindricalcoupling element 30 of the substantially cylindrical insert 32. Couplingelement 30, as shown may be configured as a male element, however, allcombinations of male and female configurations is acceptable forcoupling elements 30 and coupling end 22 in alternate embodiments of theinvention. Coupling end 22 of bullet-end component 18 fits about andengages coupling element 30 of a substantially cylindrical insert 32.The substantially cylindrical insert 32 includes a substantiallycylindrical coupling element 30 extending from a bottom surface 34 thatis opposite a top surface 36. Located in the top surface 36 is a primerrecess 38 that extends toward the bottom surface 34. A primer flash hole40 is located in the primer flash hole 40 and extends through the bottomsurface 34 into the powder chamber 14. The coupling end 22 extends thepolymer through the primer flash hole 40 to form an aperture coating 42while retaining a passage from the top surface 36 through the bottomsurface 34 and into the powder chamber 14 to provides support andprotection about the primer flash hole 40. When contacted the couplingend 22 interlocks with the substantially cylindrical coupling element30, through the coupling element 30 that extends with a taper to asmaller diameter at the tip 44 to form a physical interlock betweensubstantially cylindrical insert 32 and middle body component 28.Polymer casing 12 also has a substantially cylindrical open-ended middlebody component 28. The middle body component extends from a forward endopening 16 to coupling element 22. Located in the top surface 36 is aprimer recess 38 that extends toward the bottom surface 34 with adiffuser 50 positioned in the primer recess 38. The diffuser 50 includesa diffuser aperture 52 that aligns with the primer flash hole 40. Thediffuser 50 is a device that is used to divert the affects of the primer(not shown) off of the polymer. The affects being the impact fromigniting the primer as far as pressure and heat to divert the energy ofthe primer off of the polymer and directing it to the flash hole.

FIG. 8 depicts a side, cross-sectional view of a portion of thepolymeric cartridge case having a diffuser according to one embodimentof the present invention. A portion of a cartridge suitable for use withhigh velocity rifles is shown manufactured with a polymer casing 12showing a powder chamber 14. Polymer casing 12 has a substantiallycylindrical opposite end 20. The bullet-end component 18 may be formedwith coupling end 22 formed on end 20. Coupling end 22 is shown as afemale element, but may also be configured as a male element inalternate embodiments of the invention. The middle body component (notshown) is connected to a substantially cylindrical coupling element 30of the substantially cylindrical insert 32. Coupling element 30, asshown may be configured as a male element, however, all combinations ofmale and female configurations is acceptable for coupling elements 30and coupling end 22 in alternate embodiments of the invention. Couplingend 22 fits about and engages coupling element 30 of a substantiallycylindrical insert 32. The substantially cylindrical insert 32 includesa substantially cylindrical coupling element 30 extending from a bottomsurface 34 that is opposite a top surface 36. Located in the top surface36 is a primer recess 38 that extends toward the bottom surface 34. Aprimer flash hole 40 is located in the primer flash hole 40 and extendsthrough the bottom surface 34 into the powder chamber 14. The couplingend 22 extends the polymer through the primer flash hole 40 to form anaperture coating 42 while retaining a passage from the top surface 36through the bottom surface 34 and into the powder chamber 14 to providessupport and protection about the primer flash hole 40. When contactedthe coupling end 22 interlocks with the substantially cylindricalcoupling element 30, through the coupling element 30 that extends with ataper to a smaller diameter at the tip 44 to form a physical interlockbetween substantially cylindrical insert 32 and middle body component28. Polymer casing 12 also has a substantially cylindrical open-endedmiddle body component 28. Located in the top surface 36 is a primerrecess 38 that extends toward the bottom surface 34 with a diffuser 50positioned in the primer recess 38. The diffuser 50 includes a diffuseraperture 52 and a diffuser aperture extension 54 that aligns with theprimer flash hole 40. The diffuser 50 is a device that is used to divertthe affects of the primer (not shown) off of the polymer. The affectsbeing the impact from igniting the primer as far as pressure and heat todivert the energy of the primer off of the polymer and directing it tothe flash hole. The diffuser 50 can be between 0.004 to 0.010 inches inthickness and made from half hard brass. For example, the diffuser 50can be between 0.005 inches thick for a 5.56 diffuser 50. The outerdiameter of the diffuser for a 5.56 or 223 case is 0.173 and the innerdiameter is 0.080. The Diffuser could be made of any material that canwithstand the energy from the ignition of the primer. This would includesteel, stainless, cooper, aluminum or even an engineered resin that wasinjection molded or stamped. The Diffuser can be produce in T shape bydrawing the material with a stamping and draw die. In the T Diffuser thecenter ring can be 0.005 to 0.010 tall and the outer diameter is 0.090and the inner diameter 0.080.

FIGS. 9 a-9 h depict different embodiment of the diffuser of the presentinvention.

FIG. 10 depicts an exploded view of the polymeric cartridge casing. Acartridge 10 suitable for use with high velocity rifles is shownmanufactured with a middle body component 28 having a substantiallycylindrical open-ended polymeric bullet-end 18. The substantiallycylindrical open-ended polymeric bullet-end 18 has a shoulder 24 formingchamber neck 26 and a bullet 56 inserted therein. The substantiallycylindrical insert 32 also has a flange 46 cut therein and a primerrecess (not shown) formed therein for ease of insertion of the primer(not shown).

FIG. 11 depicts a view of the substantially cylindrical open-endedpolymeric bullet-end 18 has a shoulder 24 forming chamber neck 26 and abullet (not shown). One embodiment includes modifications to strengthenthe neck of the mouth 60 and to the internal base area 62 to reduce nosetearing and lodging in the chamber. The substantially cylindricalopen-ended polymeric bullet-end 18 illustrates a lock 58 (e.g.,0.030×0.003) and added a step to allow for the lock 58 to flex outduring firing. Polymer was added to the external area to strengthen theneck of the mouth 60 and to the internal base area 62. The interferenceof the bullet to the neck was increased by adding polymer to the insideof the neck 64 and the exit lock modified by adding an angle to the rim66.

The polymeric and composite casing components may be injection molded.Polymeric materials for the bullet-end and middle body components musthave propellant compatibility and resistance to gun cleaning solventsand grease, as well as resistance to chemical, biological andradiological agents. The polymeric materials must have a temperatureresistance higher than the cook-off temperature of the propellant,typically about 320° F. The polymeric materials must haveelongation-to-break values that to resist deformation under interiorballistic pressure as high as 60,000 psi in all environments(temperatures from about −65 to about 320° F. and humidity from 0 to100% relative humidity). According to one embodiment, the middle bodycomponent is either molded onto or snap-fit to the casing head-endcomponent after which the bullet-end component is snap-fit orinterference fit to the middle body component. The components may beformed from high-strength polymer, composite or ceramic.

Examples of suitable high strength polymers include composite polymermaterial including a tungsten metal powder, nylon 6/6, nylon 6, andglass fibers; and a specific gravity in a range of 3-10. The tungstenmetal powder may be 50%-96% of a weight of the bullet body. The polymermaterial also includes about 0.5-15%, preferably about 1-12%, and mostpreferably about 2-9% by weight, of nylon 6/6, about 0.5-15%, preferablyabout 1-12%, and most preferably about 2-9% by weight, of nylon 6, andabout 0.5-15%, preferably about 1-12%, and most preferably about 2-9% byweight, of glass fibers. It is most suitable that each of theseingredients be included in amounts less than 10% by weight. Thecartridge casing body may be made of a modified ZYTEL® resin, availablefrom E.I. DuPont De Nemours Co., a modified 612 nylon resin, modified toincrease elastic response.

Examples of suitable polymers include polyurethane prepolymer,cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer,ethylene vinyl acetate, nylon, polyether imide, polyester elastomer,polyester sulfone, polyphenyl amide, polypropylene, polyvinylidenefluoride or thermoset polyurea elastomer, acrylics, homopolymers,acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplasticfluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates,polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates,polybutylene, terephthalates, polyether imides, polyether sulfones,thermoplastic polyimides, thermoplastic polyurethanes, polyphenylenesulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides,styrene acrylonitriles, polystyrenes, polyphenylene, ether blends,styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates,epoxies, phenolics, unsaturated polyesters, bismaleimides,polyurethanes, silicones, vinylesters, or urethane hybrids. Examples ofsuitable polymers also include aliphatic or aromatic polyamide,polyeitherimide, polysulfone, polyphenylsulfone, poly-phenylene oxide,liquid crystalline polymer and polyketone. Examples of suitablecomposites include polymers such as polyphenylsulfone reinforced withbetween about 30 and about 70 wt %, and preferably up to about 65 wt %of one or more reinforcing materials selected from glass fiber, ceramicfiber, carbon fiber, mineral fillers, organo nanoclay, or carbonnanotube. Preferred reinforcing materials, such as choppedsurface-treated E-glass fibers provide flow characteristics at theabove-described loadings comparable to unfilled polymers to provide adesirable combination of strength and flow characteristics that permitthe molding of head-end components. Composite components can be formedby machining or injection molding. Finally, the cartridge case mustretain sufficient joint strength at cook-off temperatures. Morespecifically, polymers suitable for molding of the projectile-endcomponent have one or more of the following properties: Yield or tensilestrength at −65° F.>10,000 psi Elongation-to-break at −65° F.>15% Yieldor tensile strength at 73° F.>8,000 psi Elongation-to-break at 73°F.>50% Yield or tensile strength at 320° F>4,000 psi Elongation-to-breakat 320° F>80%. Polymers suitable for molding of the middle-bodycomponent have one or more of the following properties: Yield or tensilestrength at −65° F.>10,000 psi Yield or tensile strength at 73° F.>8,000psi Yield or tensile strength at 320° F.>4,000 psi.

Commercially available polymers suitable for use in the presentinvention thus include polyphenylsulfones; copolymers ofpolyphenylsulfones with polyether-sulfones or polysulfones; copolymersand blends of polyphenylsulfones with polysiloxanes;poly(etherimide-siloxane); copolymers and blends of polyetherimides andpolysiloxanes, and blends of polyetherimides andpoly(etherimide-siloxane) copolymers; and the like. Particularlypreferred are polyphenylsulfones and their copolymers with poly-sulfonesor polysiloxane that have high tensile strength and elongation-to-breakto sustain the deformation under high interior ballistic pressure. Suchpolymers are commercially available, for example, RADEL® R5800polyphenylesulfone from Solvay Advanced Polymers. The polymer can beformulated with up to about 10 wt % of one or more additives selectedfrom internal mold release agents, heat stabilizers, anti-static agents,colorants, impact modifiers and UV stabilizers.

The polymers of the present invention can also be used for conventionaltwo-piece metal-plastic hybrid cartridge case designs and conventionalshotgun shell designs. One example of such a design is an ammunitioncartridge with a one-piece substantially cylindrical polymeric cartridgecasing body with an open projectile-end and an end opposing theprojectile-end with a male or female coupling element; and a cylindricalmetal cartridge casing head-end component with an essentially closedbase end with a primer hole opposite an open end having a couplingelement that is a mate for the coupling element on the opposing end ofthe polymeric cartridge casing body joining the open end of the head-endcomponent to the opposing end of the polymeric cartridge casing body.The high polymer ductility permits the casing to resist breakage.

One embodiment includes a 2 cavity prototype mold having an upperportion and a base portion for a 5.56 case having a metal insertover-molded with a Nylon 6 (polymer) based material. In this embodimentthe polymer in the base includes a lip or flange to extract the casefrom the weapon. One 2-cavity prototype mold to produce the upperportion of the 5.56 case can be made using a stripper plate tool usingan Osco hot spur and two subgates per cavity. Another embodimentincludes a subsonic version, the difference from the standard and thesubsonic version is the walls are thicker thus requiring less powder.This will decrease the velocity of the bullet thus creating a subsonicround.

The extracting inserts is used to give the polymer case a tough enoughridge and groove for the weapons extractor to grab and pull the case outthe chamber of the gun. The extracting insert is made of 17-4 stainlesssteel that is hardened to 42-45 rc. The insert may be made of aluminum,brass, cooper, steel or even an engineered resin with enough tensilestrength.

The insert is over molded in an injection molded process using a nanoclay particle filled Nylon material. The inserts can be machined orstamped. In addition, an engineered resin able to withstand the demandon the insert allows injection molded and/or even transfer molded.

One of ordinary skill in the art will know that many propellant typesand weights can be used to prepare workable ammunition and that suchloads may be determined by a careful trial including initial lowquantity loading of a given propellant and the well known stepwiseincreasing of a given propellant loading until a maximum acceptable loadis achieved. Extreme care and caution is advised in evaluating newloads. The propellants available have various burn rates and must becarefully chosen so that a safe load is devised.

The description of the preferred embodiments should be taken asillustrating, rather than as limiting, the present invention as definedby the claims. As will be readily appreciated, numerous combinations ofthe features set forth above can be utilized without departing from thepresent invention as set forth in the claims. Such variations are notregarded as a departure from the spirit and scope of the invention, andall such modifications are intended to be included within the scope ofthe following claims.

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method, kit, reagent, orcomposition of the invention, and vice versa. Furthermore, compositionsof the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the invention.The principal features of this invention can be employed in variousembodiments without departing from the scope of the invention. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, AB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of this inventionhave been described in terms of preferred embodiments, it will beapparent to those of skill in the art that variations may be applied tothe compositions and/or methods and in the steps or in the sequence ofsteps of the method described herein without departing from the concept,spirit and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope and concept of the invention as defined by theappended claims.

What is claimed is:
 1. A method of making a polymeric ammunitioncartridge having a substantially cylindrical metal primer insertcomprising the steps of: providing a substantially cylindrical insertcomprising a top surface opposite a bottom surface and a substantiallycylindrical coupling element that extends from the bottom surface toform a circumferential surface, a primer recess in the top surface thatextends toward the bottom surface, a primer flash hole aperturepositioned in the primer recess to extend through the bottom surface,and a flange that extends circumferentially about an outer edge of thetop surface; forming a substantially cylindrical polymeric middle bodycomprising the steps of overmolding a polymer composition over thesubstantially cylindrical insert by molding the polymer composition overthe substantially cylindrical coupling element, over the circumferentialsurface and into the primer flash hole aperture to form a primer flashhole, forming a substantially cylindrical polymeric middle bodyextending from the substantially cylindrical insert, and forming asubstantially cylindrical polymeric coupling end at the end of thesubstantially cylindrical polymeric middle body; forming a substantiallycylindrical open-ended polymeric bullet-end component comprising thesteps of forming a polymeric bullet-end coupling component opposite abullet-end aperture from a second polymer composition, wherein thepolymeric bullet-end coupling component mates to the substantiallycylindrical polymeric coupling end; and adhering the polymericbullet-end coupling component mates to the substantially cylindricalpolymeric coupling end to form a propellant chamber having a bullet-endaperture opposite a primer flash hole.
 2. The method of claim 1, whereinthe substantially cylindrical open-ended polymeric bullet-end componentcomprises a shoulder positioned between the substantially cylindricalpolymeric bullet-end and the bullet-end aperture and a neck positionedbetween the shoulder and the bullet-end aperture.
 3. The method of claim1, wherein the substantially cylindrical open-ended polymeric bullet-endcomponent, substantially cylindrical polymeric middle body or both areformed from a ductile polymer.
 4. The method of claim 1, wherein thesubstantially cylindrical open-ended polymeric bullet-end component isformed from a less ductile polymer than the substantially cylindricalpolymeric middle body.
 5. The method of claim 1, wherein thesubstantially cylindrical open-ended polymeric bullet-end component,substantially cylindrical polymeric middle body or both comprise a nylonpolymer.
 6. The method of claim 1, wherein the substantially cylindricalopen-ended polymeric bullet-end component, substantially cylindricalpolymeric middle body or both are formed from a fiber-reinforcedpolymeric composite.
 7. The method of claim 6, wherein thefiber-reinforced polymeric composite contains between about 10 and about70 wt % glass fiber fillers, mineral fillers, or mixtures thereof. 8.The method of claim 1, wherein the polymeric bullet-end couplingcomponent mates is welded or bonded to the substantially cylindricalpolymeric coupling end.
 9. The method of claim 1, wherein bullet-endaperture is welded or bonded to the bullet.
 10. The method of claim 1,wherein the bullet-end aperture is crimped to the bullet.
 11. The methodof claim 1, wherein a bullet is adhesively fitted to the bullet-endaperture.
 12. The method of claim 1, wherein the bullet-end aperturecomprises one or more cannelures that interlocks with the bullet. 13.The method of claim 2, wherein the neck comprises one or more canneluresthat interlocks with the bullet.
 14. The method of claim 1, wherein theforward opening end comprises one, two, three, or more annular ringsthat mate with one, two, three, or more corresponding annular groovespositioned on the bullet.
 15. The method of claim 1, wherein the polymercomposition and the second polymer composition independently comprise apolymers selected from the group consisting of polyurethane prepolymer,cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer,ethylene vinyl acetate, nylon, polyether imide, polyester elastomer,polyester sulfone, polyphenyl amide, polypropylene, polyvinylidenefluoride or thermoset polyurea elastomer, acrylics, homopolymers,acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplasticfluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates,polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates,polybutylene, terephthalates, polyether imides, polyether sulfones,thermoplastic polyimides, thermoplastic polyurethanes, polyphenylenesulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides,styrene acrylonitriles, polystyrenes, polyphenylene, ether blends,styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates,epoxies, phenolics, unsaturated polyesters, bismaleimides,polyurethanes, silicones, vinylesters, urethane hybrids,polyphenylsulfones, copolymers of polyphenylsulfones withpolyethersulfones or polysulfones, copolymers of poly-phenylsulfoneswith siloxanes, blends of polyphenylsulfones with polysiloxanes,poly(etherimide-siloxane) copolymers, blends of polyetherimides andpolysiloxanes, and blends of polyetherimides andpoly(etherimide-siloxane) copolymers.
 16. The method of claim 1, whereinthe substantially cylindrical open-ended polymeric bullet-end componentcomprises a neck with a plurality of internal structures for supportinga bullet.
 17. The method of claim 1, wherein the substantiallycylindrical coupling element is a male coupling element with a straightskirt interlock surface that tapers to a smaller diameter at the forwardportion on the skirt tip to mate with a female coupling element of thesubstantially cylindrical polymeric coupling end.
 18. The method ofclaim 1, further comprising a diffuser positioned in the primer recessin contact with the primer and comprising a diffuser flash hole alignedwith the primer flash hole.
 19. A method of making a polymericammunition having a substantially cylindrical metal primer insertcomprising the steps of: providing a substantially cylindrical insertcomprising a top surface opposite a bottom surface and a substantiallycylindrical coupling element that extends from the bottom surface toform a circumferential surface, a primer recess in the top surface thatextends toward the bottom surface, a primer flash hole aperturepositioned in the primer recess to extend through the bottom surface,and a flange that extends circumferentially about an outer edge of thetop surface; forming a substantially cylindrical polymeric middle bodycomprising the steps of overmolding a polymer composition over thesubstantially cylindrical insert by molding the polymer composition overthe substantially cylindrical coupling element, over the circumferentialsurface and into the primer flash hole aperture to form a primer flashhole, forming a substantially cylindrical polymeric middle bodyextending from the substantially cylindrical insert, and forming asubstantially cylindrical polymeric coupling end at the end of thesubstantially cylindrical polymeric middle body; forming a substantiallycylindrical open-ended polymeric bullet-end component comprising thesteps of forming a polymeric bullet-end coupling component opposite abullet-end aperture from a second polymer composition, wherein thepolymeric bullet-end coupling component mates to the substantiallycylindrical polymeric coupling end; adhering the polymeric bullet-endcoupling component mates to the substantially cylindrical polymericcoupling end to form a propellant chamber having a bullet-end apertureopposite a primer flash hole; inserting a primer inserted into theprimer flash hole aperture; at least partially filling the propellantchamber with a propellant; and frictionally fitting a bullet in thebullet-end aperture, wherein the primer, the propellant and the bulletform a sealed propellant chamber.